At least 18 people have been killed in an explosion near a governor's office and mosque in southern Afghanistan.
The blast near Kabul killed a Nato soldier
A suicide bomber was stopped at a checkpoint in the town of Lashkar Gah in volatile Helmand province, when he triggered his device, officials said.
Separately, a bomb placed under a bridge has struck a convoy of Nato-led troops in the Afghan capital, Kabul.
A Nato soldier, named as Corporal Giorgio Langella, and an Afghan child were killed.
Nato's mission in Afghanistan, Isaf, said five soldiers were injured in the blast, along with five Afghan civilians.
It is thought they were travelling in a vehicle behind the Nato convoy when the explosion happened.
The attack in Lashkar Gah took place at the first ring of security outside the compound housing the governor of Helmand province, Mohammed Daoud Safi.
MAJOR RECENT ATTACKS
22 Sept: 19 workers die as their bus is bombed and shot at in Kandahar province
18 Sept: In Herat motorcycle bomber kills at least 10 people
8 Sept: Suicide car bomb in Kabul kills two US soldiers and 14 others
28 Aug: 17 die in bombing in southern province of Helmand
3 Aug: 21 killed in bomb in Kandahar province
He was inside the compound and not hurt in the blast, police said.
"This was a suicide attack. A man carrying explosives attached to his body was stopped by police at a control point and then activated his bomb," police General Mohammad Nabi Mullahkhail told the AFP news agency.
He said three of the dead were police officers.
It was reported that 12 were civilians and another three were from the Afghan army.
At least 17 people were injured in the attack.
Many of the victims were Afghan pilgrims seeking permission to travel to Mecca in Saudi Arabia for the Hajj, a spokesman said.
Tuesday's attacks came on the day that US President George W Bush held talks with Afghan President Hamid Karzai.
At a joint news conference, the US president assured Mr Karzai of America's continuing support for Afghanistan.
Suicide bombings are becoming more common and more deadly
"Our country will stand with the free people of Afghanistan. I know there is some in your country who wonder whether or not America has got the will to do the hard work necessary to help you succeed.
"We have got that will and we are proud of you as a partner," Mr Bush said.
On Wednesday they will hold a trilateral dinner with Pakistani President Pervez Musharraf at the White House.
But the two South Asian leaders are still blaming each other for the resurgence of extremism and violence in their region, says the BBC's Jonathan Beale in the US.
Mr Karzai said Pakistan must crack down on hardline Islamist schools, since "there will not be an end to terrorism unless we remove the sources of hatred in madrassas and the training grounds".
General Musharraf fired back that Mr Karzai needed to wean his people away from Taleban Islamists, and "the sooner Mr President Karzai understands his own country's environment, the easier it will be for him".